Submitted by Kay1636 t3_z6azff in explainlikeimfive
I'm sorry for asking this. But I always wondered how come cows and buffaloes who only eat grass and stuff get so big? Here I am working out 5 days a week with my job and eating a lot of meat and getting normal results. Sorry again, I have no intention of annoying anyone.
I love how this reads like a buffalo complaining about their daily routine at first glance.
Yes, thank you for your explanation!
Plants are mostly made of cellulose, which is a bunch of sugar molecules linked into a strong chain.
Humans can't digest cellulose. For us, eating grass is just fiber, zero calories.
For herbivores like buffalo and cows, they have multiple stomachs and special enzymes and bacteria that let them break down cellulose into usable sugars. For herbivores, eating grass is like eating bread for humans. It's a form of carbs for them.
The other factor is large herbivores spend hours and hours a day eating like 50 lbs of grass. If you eat 10 loaves of bread a day you'd be 800 lbs in a few years too.
Thank you for your answer! I totally forgot that we cannot digest cellulose and cows have four stomach that help them digest grass.
They eat a lot of calories. Herbivores have enzymes that let them digest "insoluble fiber" aka cellulose, aka plant fiber. They get a lot more nutrition from plants than humans. These enzymes break open the plant cells, giving them access to proteins and fats not available to us. Plus they never stop eating.
This is fascinating. I did not know this.
Then are humans herbivores? If we are vegetarian, and eat some plant stuff but not all, why? Why don't we get the special enzymes? It'd be cool to munch on grass. We already eat vegetables so what makes the key difference?
Cows and Buffaloes literally chomp down on dried grass. DRIED GRASS! Why didn't we get those enzymes? They sound cool.
We're not herbivores (your teeth are one of the best indicators here, no herbivores have front teeth like ours). The main reason we don't have enzymes like cows is because there was no evolutionary pressure for us to, our ancestors have been able to get by on more easily digested vegetation and meat.
On a similar vein, the reason we can't eat raw meat like other meat-eating animals is because digesting it takes enzymes that we lack, which we probably lost because they take energy to produce so our ancestors eating cooked meat could survive more easily without them.
Thank you this is nice.
Basically, because those special enzymes (and the gut mechanisms to make use of them) are a trade-off. It takes a long time and a lot of digestion to break down tough plant materials like cellulose into stuff an animal body can use. Herbivorous animals have long, complicated digestive tracts, especially the ruminant (four-stomached) ones like cattle and buffaloes, and they spend all day long grazing, chewing, fermenting, and re-chewing stuff like grass to make it useable. (Some don't have these long digestive systems and instead rely on easier plantstuffs like fruits and leaves, but then, those are the kinds of things that we can eat too.) This is worth it for them, evolutionarily, because it gives them access to a semi-exclusive food source.
Humans, along with other omnivore/carbivore species, have opted for a different strategy. Instead of investing a bunch of our time, energy, and body mass into specialized plant-digesting equipment, we developed stuff that makes us better hunters and more discerning gatherers. We can't eat grass, but we don't have to spend 12-18 hours a day doing it, because we can just climb a tree and eat a banana or catch a squirrel instead and get the same amount of nutrients. Obligate carnivores like cats have really simple digestion and can't digest any plant material, but they can sleep 18 hours a day instead. Dogs are slightly more carnivorous than us, and will supplement their diets with plants where necessary, but still mostly need meat. We humans are juuust about herbivorous enough to get by on plants alone if we choose to, but we have to be careful about it, and usually fare best with some animal product supplementation.
Well they have enzymes, and special bacteria ... as well as multiple stomachs and have to rechew their food over and over after its been in this stomachs. AND if we had that ability, we'd have no fiber in our diets, which would lead to high cholesterol and high rates of colon cancer.
Besides, do you want to be chewing 13 hours a day?
Why would we not have fiber?
The fiber in our diets he refers to is the fiber from fruits and vegetables that we cannot digest. I imagine if we could digest the grass it wouldn’t count towards the fiber that aids in passing matter through the digestive tract as it would have been digested already
Is that why cow poop is gooey and not like... Well, like a banana shape?
Thank you for your explanation! I remember this topic being taught in my high school years but I forgot.
Then we eat them
The largest terrestrial animals have always been herbivores, elephants, rhinos, mammoths, giant tree-munching dinosaurs, and so on. I’m not sure why you think that would be different for buffalo.
Being an herbivore means that you have ready access to vast quantities of food that most animals can’t extract nutrition from, but you can. Having access to large amounts of food allows for gigantism in animals, and being a large herbivore means that the predators capable of taking you down must either be large and powerful, or run in packs. Being large also means you can support large fat stores which help you to get through leaner times, and also withstand very cold weather.
Thank you for your answer!
but surely there are many herbivores in the wild so the food is limited no?
My brother in Christ. Prairies.
i know - but surely if they all eat so much is that enough for them?
Have you ever been outside?
whats your point?
Because the lower down the food chain you go, the more calories energy a food contains.
So imagine a simple food chain: Sun > Grass > Buffalo > Bear.
To make 1kg of Buffalo, you need 10kg of grass.
To make 1kg of bear, you need 10kg of Buffalo.
The bear needs the caloric equivalent of 100kg of grass, whereas the buffalo requires only 10kg because it eats the plant directly.
From a calorie/energy point of view, the further up the food chain you go, the more energy is lost at each stage and the harder it becomes to get enough energy, which reduces your potential to grow your population.
This is why there will always be significantly more buffalo than bears.
In terms of efficient calories, it is best to be a plant and take your energy directly from the sun.
But since animals cannot do that, being a herbivore is the next most efficient way, with the minimum possible energy lost.
WoW! Thanks for your explanation!
No problem, my first degree was in Biology and this is precisely how we were taught it.
Cattle, Elephants, Hippos, Rhinos, Giraffes these are all large land mammals. They all get large the same way. They eat a lot of food.
Yes, I see. Thank you!
You're talking about two completely different species (humans & American Bison). While protein is essential for us to build muscle, that isn't the case for all animals, not that there isn't protein in vegetation. Some of the largest land animals (dinosaurs) were plant eaters.
The answer to your question isn't why are herbivores so big now? It's why are they so small? If anything, you think about the era of dinosaurs, you had mega animals who ate megafauna. Huge massive plants and nutrition there that fueled the growth of mega animals. Even the mammals of that time, and since then until relatively recent history, were massive. Giant rats compared to today. Giant sloths. Whatever we had today, there were giant versions before.
Humans, smaller than anyone else, just used the environment better. We burned it all down and killed the megafauna, and thus starved out the mega animals to become the apex there. So grass became the most common plant around, and those animals that thrived on grass stuck around. Those that didn't, struggled or went extinct. I think it's the book The Sixth Extinction which goes through this history very interestingly.
In the modern context, your question then comes down to how people massively underestimate veggies now. We've been taught that meat is why human brains evolved, why we grow muscles, and so on. Meat companies literally paid schools to put the food pyramid in with meat and dairy at the top and suggest it was the 'best' food. The top of the pyramid. And that marketing stuck with us and our assumptions about food.
But you take buffaloes, elephants, gorillas, giraffes, and other large land mammals and you see that the largest and the strongest are herbivores. If you think about what actually fuels a mammal's brain (glucose) then those question marks start to creep in. Protein wasn't the answer. Eating a lot more calories (and the particular nutrition) that fueled and allowed more complex thinking was.
Obviously, those animals can process grass. We cannot. We have to farm and grow different plants. But even for humans now, we get 2/3s of our protein on average from vegetables even with such a meat heavy diet today. It's just interesting that by historical standards, today's mammals are actually tiny compared to their predecessors.
What we can take from it for the modern world, though, is we shouldn't assume meat is the best nutrition. Your body needs nutrition. It doesn't really matter if it comes from an animal or a plant for that sake. You can be healthy eating meat or healthy eating a plant-based diet if either are well planned (both have respective risks and rewards). The biggest separator now, though, why humans are taller than ever, is more because total calories is up. The basic formula of calories in versus calories out explains most of this. Even for humans, we're taller than past generations because of this. We eat a lot more calories in childhood than we used to, so we grow more. As kids, that means growing taller. As adults, it means growing sideways.
But yeah, ELI5, is that we underestimate veggies. Even in terms of what you say about working out 5x per week. Meat isn't the crucial factor. Enough nutrients is (esp. in terms of enough nutrients absorbed). Quantity of protein is more important than quality of protein which is more important than timing of protein. You may also be comparing "normal results" to 'influencers' who are on steroids. So that's a whole other ball game. Almost all the popular fitness guys are on the juice. So "normal results" will differ massively there.
Thank you for your explanation and taking my question seriously! Yes my workout and diet gives me normal results and I'm happy with them because I'm not on juice. Indeed the dinosaurs of past were huuuge and our buffaloes or today are basically very smol compared to them. Thanks again for going in depth on this topic!
If buffalos have got you thinking, I'm gonna blow your mind by telling you about elephants and brontosauri. Or even gorillas--these bulky beasts get super swole by eating plants.
You don't need meat to get big. Especially when you have a digestive system that is capable of getting nutrition from non-meat sources. Lots of animals have evolved different digestive systems than us. They get more out of the plants that they eat than we do.
(Heck, even humans don't need meat to get big. We just need protein--and this can come from many non-meat sources.)
Thanks for your answer!
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You aren't annoying anyone, this isn't a terrible question.
But, the answer is, why wouldn't they? You cannot apply the rules of human nutrition to other animals. Let me flip your logic for a second.....
There are jungle cockroaches that can run 150 times their body length in one second, and can lift 20 times their body weight, that eat nothing but rotting wood. OBVIOUSLY, if you go out and eat a straight diet of rotting wood, you won't et that strong or fast.
Humans are not good at digesting grass. We lack the enzymes, physical structures (like multi-chambered stomachs and grinding teeth), gut microbes, and lifestyle to get the most out of grass and other tough plants, unlocking the nutrition.
We lack the DNA, growth hormones, sex hormones, bone structure, and life cycle (ontogeny: the study of development and life cycle) to turn into giant muscular tanks, in the same way buffalo lack our ability to live to 60-70 years.
Thank you for taking this question seriously! And thanks for your explanation!
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PhilosopherDon0001 t1_iy0ddd1 wrote
Your entire day (whole life, really) revolves around eating. Yeah, grass is low in calories, but when you are basically chewing from the moment you wake up to the moment you go to sleep ,You can put down quite a few calories.
Also, there's only a couple of things that can eat them.